18th century jailer's flintlock key gun.
https://diqn32j8nouaz.cloudfront.net...o_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...314#post154264
https://www.homemadetools.net/forum/...6956#post84708
https://www.homemadetools.net/forum/...171#post126210
